Valve plate for a hydraulic pump or motor



Aug. 11, 1970 J. T. M. WRIGHT 3,523,673

VALVE PLATE FOR A HYDRAULIC PUMP OR MOTOR Filed March 13, 1968 2 Sheets-Sheet 1 I ENT'O ATTORNEYS 1970 J. T. M. WRIGHT 3,523,678

VALVE PLATE FOR A HYDRAULIC PUMP OR MOTOR Filed March 13, 1.968 2 Sheets-Sheet 2 ATTORNEYS United -'States Patent Office 3,523,678 Patented Aug. 11, 1970 3,523,678 VALVE PLATE FOR A HYDRAULIC PUMP OR MOTOR John Thomas Matthew Wright, Southport, England,

assiguor to Joseph Lucas (Industries) Limited, Birmingham, England Filed Mar. 13, 1968, Ser. No. 712,760 Int. Cl. F16k 1/34; F04b 21/00 US. Cl. 251-316 3 Claims ABSTRACT OF THE DISCLOSURE A valve plate for a hydraulic swash plate-type pump or motor is formed in two pieces having aligned apertures therein of differing sizes, to define recesses in the face of the valve plate which is disposed adjacent to the body to accommodate seals.

The invention relates to hydraulic pumps or motors of the kind in which there is a body in which is rotatably mounted a rotor having spaced bores containing reciprocable pistons, the body having an inlet and an outlet for liquid to be pumped, there being an apertured valve plate non-rotatably mounted between the body and the rotor through which the liquid can enter and leave the bores in the rotor as the latter rotates, there being recesses surrounding the apertures in the face of the valve plate to accommodate seals disposed between the valve plate and the body.

The object of the invention is to provide a valve plate for a hydraulic pump or motor of the kind specified in a convenient form.

In accordance with the present invention a valve plate for a hydraulic pump or motor of the kind specified is formed in two pieces having aligned apertures therein of differing sizes, the arrangement being such that when the two pieces are placed in juxtaposition, there are defined recesses in the face of the valve plate which is intended to be disposed adjacent to the body and to accommodate the seals.

The invention will now be described by way of example with reference to the accompanying drawings in which:

FIG. 1 is a cross-sectional view of a pump incorporating a valve plate constructed in accordance with this invention.

FIG. 2 is a front elevation view of a valve plate with sealing members omitted.

FIG. 3 is a cross section view on the line 33 in FIG. 2.

FIG. 4 is a cross-sectional view on the line 4-4 in FIG. 2.

The valve plate illustrated is intended for use in a swash plate type pump as shown in FIG. 1 in which there is a body 1 containing a rotatable rotor 2 having a plurality of angularly spaced bores 3, containing respective pistons 4, extending outwardly thereof and into contact with an angularly disposed or disposable swash plate 5 which is non-rotatably mounted within the body 10. Between the opposite end of the rotor 2 and the adjacent face of the body 1, in which an inlet passage 6 and an outlet passage 7 are provided, is a valve plate 10 illustrated in FIGS. 2, 3 and 4.

This valve plate 10 has two pairs of generally kidney shaped ports 11, 12 respectively formed therein, and these afford alternate communication between the bores in the rotor 2 and the inlet and the outlet passages 6, 7 as the rotor rotates, to provide passages for the entry and escape of fluid from the rotor bores 3.

The valve plate 10, as illustrated in FIGS. 1, 3 and 4, is formed in two separate pieces 10a, 10b, the former being provided With the openings 11, 12, and the latter being provided with larger openings 13, 14 respectively, which are aligned with, and encompass the pairs of openings 11, 12 in the piece 10a of the valve plate.

The difference in the sizes of the openings in the pieces 10a, 10b of the valve plate is sufiicient to define respective recesses surrounding the smaller openings 11, 12, and these recesses accommodate respective sealing assemblies comprising two back-to-back L-shaped parts 15, defining between them an opening accommodating a ring 1 6.

These assemblies are arranged to abut against the adjacent face of the body and have their edges chamfered as illustrated, so as to provide suitable areas for the pressure balancing of the valve plate whereby it is maintained in a position with respect to the rotor 2 to permit leakage between them for the purpose of lubrication, but in which this leakage is maintained at a practical minimum.

As illustrated in FIG. 4, disposed between the two pieces 10a, 10b of the valve plate are disposed two further sealing assemblies comprising, in each case, an L- shaped ring 17 enclosing a sealing member 18. These sealing assemblies are provided in recesses formed in the piece 10a, and abut against the adjacent face of the piece 10b, there being means for supplying fluid under pressure to these recesses in the form of openings 19, which communicate with the bores of the rotor in turn as the latter rotates, to provide pressure balancing of the two pieces of the valve plate. There are further aligned holes 20 in the two pieces 10a, 10b, of the valve plate, through which dowels (not shown) pass into the body to prevent rela tive rotation between the pieces of the valve plate and also between the valve plate and the body.

With this arrangement it is possible to form the openings in the valve plate pieces by relatively inexpensive manufacturing methods such as stamping, and then to fit the pieces together so that the appropriate recesses are defined to receive the sealing assemblies 15, 16, thus avoiding the normal relatively expensive milling operations required to provide these recesses. The recesses to accommodate the sealing assembly 17, 18 are more easily produced, since these are circular instead of kidney shaped as in the case of the openings 11, 12, 13 and 14.

It is to be understood that the invention can also be applied to other forms of pump such as radial piston-type pumps and also to hydraulic motors.

Having thus described my invention what I claim as new and desire to secure by Letters Patent is:

1. An apertured valve plate for a hydraulic swash platetype machine comprising two flat pieces having aligned similarly shaped apertures therein of different sizes, the References Cited two pieces being placed in juxtaposition to define recesses UNITED STATES PATENTS in one face of the valve plate which is intended to be dispOsed adjacent to a body of the machine, and seals ac- 226,059 3/1880 Glnem 251361 X commodated in these recesses respectively. 2893430 7/1959 Hon 251 316 X 5 2,908,293 10/1959 Johnson 251-317 X sea ls irl 13;; i ni lfli i i iisilierii c mtare ssi iz iiie r z 2969810 1/1961 Dudley 251 283 X bets 3,297,052 1/1967 Robinson 137-625.21

3. A valve plate as claimed in claim 1 having further ARNOLD ROSENTHAL Primary Examiner seals defined in respective spaces defined between the two 10 US, Cl. X R

pieces of the valve plate. 25 l172; 103162 

